Maths end of year revision (year 7)

Question 1

What is positive correlation?

Answer 1

Positive correlation is when one side on a scatter graph gets a bigger number e.g. shoe size and how tall you are, they positively correlate because one affects the other.

Question 2

What is negative correlation?

Answer 2

Negative correlation is when one side gets bigger and the other gets smaller, e.g. grades and hours on video games, if one gets higher then the other gets lower.

Question 3

What is no correlation?

Answer 3

No correlation is when both variables don’t depend on each other. e.g. IQ and how tall you are, they don’t correlate because neither goes up or down when the other thrives or not thrive therefore they don’t correlate.

Question 4

What is a venn diagram?

Answer 4

A venn diagram is a way to organise information in a visual way this means that we can easily see information.

Question 5

What is a prime number?

Answer 5

A prime number is a number that only has 2 factors (1 and itself)(1 is not a prime number). 2 is the only even prime number.

Question 6

How do you find the product of the prime factors?

Answer 6

If you write 51 as the product of its primes (factors) would be 51=3x17. You draw a factor tree then separate the numbers into their factors. e.g. Write 60 as the product of its prime factors.
60=(2) and 30= (2) and 15= (3) and (5). You don’t need to write down the factor pair 1 and 60 because 1 isn’t a prime number and it doesn’t split 60 into any other factors. 60=2x2x3x5.

Question 7

How do you work out the Highest Common Factor and the Lowest Common multiple?

Answer 7

You work out the HCF and the LCM of 12 by drawing a factor tree and putting your answer into a Venn diagram. You find the HCF by multiplying the numbers in the intersection. You find the LCM by multiplying all the numbers in the Venn diagram.

Question 8

What is a square and cubed number?

Answer 8

A square number is a number multiplied by itself twice (5x5) and a cubed number is a number that is multiplied by itself 3 times (5x5x5). A square root is a factor of a number that you can multiply by itself to get that number. A cube root is the same except that you can multiply by itself twice to get that number.

Question 9

How do you find the perimeter?

Answer 9

You find the perimeter by adding up all the sides e.g. 10cm + 10cm + 5cm + 5cm = 30cm. Perimeter = 30cm.

Question 10

How do you find the area?

Answer 10

You find the area by multiplying the length and width together e.g. 10x5=50cm squared. Area = 50cm squared.

Question 11

How do you find the area of a triangle?

Answer 11

You find the area of a triangle by doing half x base x the perpendicular height. e.g. Area=half x 10 x 8
= 5 x 8
=40cm squared
Area=40cm squared.

Question 12

What are indices?

Answer 12

Indices are numbers to the power of another numbers (cubed and square numbers). e.g. S x S x S x T x T x U = s3 t2 u

Question 13

What are fractions?

Answer 13

Fractions are parts of a whole e.g. 1/2, 1/4, 1/3 etc.

Question 14

How do you change a decimal into a fraction and vice versa?

Answer 14

You make a decimal into a fraction by putting a decimal over 100 e.g. 0.25 = 25/100. Then you divide 25 and 100 by 25 because 25 fits equally in both 25 and 100.

Question 15

How do you add fractions together?

Answer 15

You add fractions by adding the numerators together but not the denominators. e.g. 1/3 + 1/3 = 2/3.

Question 16

How do you subtract fractions?

Answer 16

You subtract fractions by only subtracting the numerator and not the denominator. E.g. 4/9 - 3/9 = 1/9. However if the denominators are not the same then you have to multiply the fraction to get the same denominator. E.g. 7/12 - 1/2. 1/2 x 6 = 6/12. 7/12 - 6/12 = 1/12.

Question 17

What is probability?

Answer 17

Probability is how likely something to happen out of a whole number (fractions). E.g. I roll a six sided dice (fair)
What is the probability of me rolling
1)2 (2)Even number (3)a number greater than 4 (4)7 (5)a number less than 7

1)=16.67% (2)=50% (3)=33.33% (4)=0% (5)=100%

Question 18

How do you find a fraction of an amount?

Answer 18

You find a fraction of an amount by putting the number over 1 (e.g. 30/1)then multiply your fraction by your whole number. E.g. 2/7 of 30
2/7 x 30/1 = 60/7 = 8 4/7

Question 19

What is an angle?

Answer 19

An angle is the space between two intersecting lines or surfaces at or close to the point where they meet. E.g. 180°

Question 20

What is a graph?

Answer 20

A graph shows a collection of points whose coordinates make a specific shape. E.g. (-2,0), (-1,1), (0,-2), (2,4), (-2,0)

Question 21

What is an average?

Answer 21

There are 4 types of averages (mode, medium, mean and the range) the mode is the number the comes up the most. The medium is the number in the middle when all the numbers are put in order. The mean is when you add up all the numbers and then divide by the number of items. The range is the biggest number subtract the smallest number.

Question 22

What is a pie chart?

Answer 22

A pie chart is a circular chart that organises information into segments inside the pie chart. This chart works well because you can see which variable is doing the best.